Aerial-bomb fuse



Aug. 16, 1927. 1,639,075

v F. w. BOLD Filed Dec. 3. 1923 5 Sheets-Sheet 1 ,111 venlar 6 g d fl toriu g Aug. 16, 1927.

4 F. w. BOLD AERIAL BOMB FUSE Filed Dec. 3. 1923 5 Sheets-Sheet 2 .191 vefllar Aug. 16, 1927.

F. w. BOLD AERIAL BOMB FUSE Filed Dec. 5. 1923 Sheets-Sheet 3 W 6 W tlfiborzug 1,639,075 1927- F. w. BOLD AERIAL BOMB FUSE F d D 5, 1923 5 Sheets-Sheet 4 Aug. 1 1927.

F. W. BOLD AERIAL BOMB FUSE Filed Dec. 5, 1923 5 Sheets-Sheet 5 9. v 6 WWW Patented Aug. 16, 1921.

UNITED STATES 1,639,075 PATENT OFFICE.

-EBEDERICK .W. BOLD, OI CHELSEA, MASSACHUSETTS, ASSIGNQR TO CHARLES PEARSON, OF BROOKLINE, MASSACHUSETTS.

AER IAL IBOMB FUSE.

My present invention relates to fuses, and more particularly to a time controlled detonating fuse for use in connection with aerial bombs and the like, and is a continue ation, in part, of my copending application,

Serial No. 648,378, filed June 28, 1923.

In designing a controlling fuse for determining the timeof detonation of an aerial bomb, a considerably different problem is m presented from that presented by the designing of a controlling fuse for high explosive shells thrown from a. gun. While the shock to fuse controlling mechanism when the shel to which the fuse is at- 15 tached is discharged from a gun is a heavy. shock and, the timing control mechanism for the fuse must be designed to withstand such" shock, yet such shock is comparatively slight when compared to the shock imparted to the timing mechanism of a controlling fuse attached to an aerial bomb when such bomb strikes its target after being thrown from any considerable height. In comparison, the shock imparted to a timing fuse attached to -a high explosive shell is a .cushioned shock as compared to the hammer blow shock imparted to the timing mechanism of a fuse attached to an aerial bomb. Y This is for the reason that the shock imparted to the high explosive time train is due to comparatively slow burning powder while the shock imparted to the aerial bomb timing fuse train is imparted when the aerial bomb strikes the earth or a building or any other 85 place where its flight is suddenly halted.

Attempts have been made to adapt timing train mechanism for fuses suitable for detonating high ex losive shells to like use to detonating the c arge in an aerial bomb, but 40 in no instance of which I am aware has this been successful. The greatest use in present day warfare is the advance mining of a selected territory prior to an attempt on the. part of shock troops to take such mined territory from the enemy. Under these conditions. therefore, itis necessary or atleast advisable to mine the desired territory a coniderabIe-time in advance of the expected assault, which time usually ranges from thirty sixto seventy two hours and as the shock of landing of the aerial bombmust positively set in motion the timing train for detonating the fuse, and when it is remembered that the number of such aerial bombs may be dropped in a swamp or lakes, or during the time elapsing between the dropping thereof and the detonating of the charge therein, the country may be. subjected to heavy rains or even floods, it will be apparent that it is essential to absolutely -prevent access of moisture or dirt of any sort to the timing train asthe presence thereof would revent the functioning of the timing train and therefore the detonating of the explosive charge at the. desired time. As the timing trains for controlling the detonating of explosive charges in high explosive shells are primarily of two classes, viz those which detonate the charge on the shell reaching its destination and those which detonate the charge a predetermined time after the shell leaves the gun, and as such time in any event is exceedingly short as compared with the length of time" the timing train of an aerial bomb must operate, it is practically impossible to adapt a fuse of a high explosive shell to an aerial bomb.

In my present invention I have obviated the objections above noted and have designed a fuse for detonating the charge of an aerial .bomb, the timing train of such fuse being positively set in motion by mechanism operated on the stopping of the flight of the bomb and my improved deviceis pgrovided with means for absolutely preventing the access of moisture or dirt of any kind to the timing train regardless of the length of time of exposure of the aerial bomb to moisture.-

Further, this means will operate to 'startt-he timing train inoperation whether the bomb strikes nose down, tail down, or on its side,

and in fact, "is operable regardless of'the position of the'bomb when it is halted in its flight. In carrying out my invention, I arrange the fuse and the timing train therefor in a chamber in which is arranged the detonating charge for positively exploding the main explosive charge of the aerial bomb and arrange the starting mechanism in a line substantially parallel to the longitudinal axis of the bomb. Such starting mechanism is made up of a plurality of elements, the displacement of either of which is suflicient to move the operating mechanism to starting position.

Associated with the mechanism for starting thetiming train in operation is a safety device, which safety device is securely held in position by means that is only removed when the aerial bomb isplaced in position just-prior to the placing of .the bomb in the conveying apparatus, such as an airplane or lighter than air flying machine. On placing the aerial bomb in position on its carrier, the safety device. above referred to as being associated with the timing train starting mechanism, is secured to any convenient portion of such carrier and the act of releasing or dropping the aerial bomb from the carrier is suflicient to withdraw the safety device to allow operative movement of the starting mechanism. This feature is of great importance as it allows handling of the aerial bomb without danger of premature detonation of the charge thereof while yet being readily removed to allow operation ofthe device. As the safety device above referred to must necessarily protrude from the outside of the timing fuse or aerial bomb and connects, or is associated with,

.Inechanism located within the interior of the timing fuse, there is necessarily produced a passage through which water may pass to the interior of the timing fuse. In order to prevent this contingency, I have associated the safety fuse with the timing train starting mechanism in such a way that when the mechanism is operated to start the timing train, the passage heretofore occupied by the safety device is effectually covered and access of moisture prevented from seeping therethrough into. the interior of the use.

Devices of this character, when once as sembled, must be incapable of being disas sembled without detonating the explosive charge as otherwise the enemy on coming across one of such bombs could readily-dis assemble the same and defeat the object for which the bomb was deposited. I have therefore, devised an improved structure whereby the various parts may be assembled in position so as to be operated to carry out the purpose for which the device was de signed and which is incapable of being (Ii?- assembled.

When assembled, the assembled parts can never be inspected. It may sometimes happen that.the timing train is accidentally started in motion as, for example, it may happen that the safety pin has been pulled out and the bomb with the fuse attached is dropped from any height. Under such circumstances, the timing train will be started .in motion. This may happen before the timing train is set to detonate the charge at any desired time and it is possible that the timing train is set at zero and would, ordinarily, immediately detonate the charge. To prevent such a contingency happening and to provide absolute safety in the handling of such devices I have associated with the firing pin release mechanism a mechanism that is connected with the timing train so that, if the timing train is set at zero, yet

may be set.

a predetermined length of time must elapse before the firing pin can be released. I have arbitrarily set such limit at five minutes as ordinarily such lengthof time will be sufficient to allow persons in the immediate Vi cinity to depart therefrom in safety, though itis obvious that any limit of time desired I consider this an important feature of my invention and as I am advised that the same is new, I desire to claim the same broadly.

The principal object of my invention. therefore, is an improved starting means for starting the timing train of a fuse in opera tion.

A further object of my invention is an improved means for preventing access of moisture or dirt to the timing train of the fuse.

A still further object of my .invention is an improved setting arrangement for denoting the time of detonation of the fuse with respect to the time of starting of the timing train.

A further object of my invention is an improved safety means for preventing accidental detonation of the fuse.

Other objects andnovel features of the construction and arrangement of partscomprising my improved device will be apparent as the description of the invention progresses.

In the accompanying drawings illustrating the preferred embodiment of my invention,

Fig. 1 is what may be termed a front ele- Vation;

Fig. 2 is a side elevation;

Fig. 3 is a schematic view of an airplane utilized as a carrier for my improved device with the device shown in position on an aerial bomb.

Figs. 4 and 5 are vertical sectional elevations on the line 44. of Fig. 1 of the portions represented by the lines A and B respectively, Fig. 4. being located above Fig. 5;

Fig. 6 is a plan view ofFig. 4:;

Fig. 7 is a fragmentary elevation of a portion of the time fuse showing the indicating mechanism for denoting the setting of the timing train;

Fig. 8 is a fragmentary sectional plan view on the line 88 of Fig. 4.;

Fig. 9 is a fragmentary sectional plan view on the line 99 of Fig. 5;

Fig. 10 is a fragmentary sectional plan View on the line 10-10 of Fig. 5;

Fig. 11 is a fragmentary sectional plan view on the line 1111 of Fig. 5;

Fig. 12 is a fragm'entar sectional plan View on the line 1212 of ig. 5;

Fig. 13 is a fragmentary sectional plan view on the line 1318 of Fig. 5;

Fig. 14 is a fragmentary sectional plan view on the line 1%14 of Fig. 5;

lit)

Fig. is aifragmentapy sectional plan a body, preferably cylindrical in shape and provided atone end with a hole 11, the outer end of which is threaded at 12-to receive the threaded portion of a plug 13 provided on its outer end with a noncircular section 14. The end of the plug 13 remote from the non-cir cular section 14 is bored at 15 and in this bored portion 15 is slidably mounted a rod 16; This rod 16 is rovided intermediate its 7 ends with a circumferential groove 17 which acts as a seat for a split ring 18 and the end of the rod 16 is cupped, as indicated at 19, to provide a seat for a ball 20. The longitudinal axis of the rod 16 lies parallel to, but

eccentric with, the longitudinal axis of thebod member 10. The body member 10 at the bottom of the hole or chamber 11 and in alignment with the axis of the rod 16 is drilled to a suitable depth to receive as a driving fit a member 22, the interior of which is drilled at 23 and the upper end of the drilled portion 23 is tapered at 24, mergin into a perforation through which is slid-w ab y mounted a rod or shaft 25. The upper end of this shaft is cupped at,26 and forms a seat for the ball 20 above described. Intermediate the ends of the shaft 25, and

preferably formed integral therewith, is an enlarged taper portion 27 which engages with the taper 24 and forms a tight joint to prevent passage of moisture or dirt through the hole in the upper end of the member 22. The body member 10 is provided with a transverse hole 28 which hole also asses through the end ofthe member 22 in the interior of which is formed the tapered portion 24. The shaft 25 between the taper portion 27 and the cup" seat 26 is drilled, as indicated at 29, and through the holes 28 and 29 is ordinarily passed a pin 30 provided at its outer end with an eye 31 and through which passes a cotter pin 32. Screwed into the body member 10 above and below the pin 30 are eyes 33 and through which passes the cotter pin 32. It is obvious from the above that, with the pin-32 passing through the hole 29 in the shaft 25, such shaft will be prevented from longitudinal movement and that this condition will prevail as long as the pin 30 is held in position by the cotter pin 32. Secured to the top end of the member. 22 is a pin 34 for a purpose to be hereinafter described. Surrounding the lower part of the shaft 25 and lying between the under face of the tapered portion 27 and the lower part of the hole 23 is a com presslon spring 35. which tends to force the shaft 25 upward, as viewed in Fig. 4, to bring the tapered portion 27 into engagement .With the taper 24. The shaft 25 ex- 1 tends downwardly through the body 10 in a manner and for a purpose to be hereinafter described. The end of the body remote from the hole or chamber 11 is reduced in diameter and the portion of this end adjacent the full diameter of the'body 10 is threaded at 36 to receive the corresponding threads 37 on the interior of the tubular end of a detonatingcharge holding member 38. The upper end of the detonating charge holding device 38 is externally threaded at 39 to receive the internally threaded end of an enclosing casing 40, which casing is of substantially the same internal diameter as the external diameter of the member 38 and is of a length slightly greater than the length of such member 38. The exterior of the enclosing casing 40 adjacent the full diameter of the body 10 is threaded at 41 to enable the entire mechanism to be screwed into position on the aerial bomb 42.

The lower end of the body 10, as viewedin Fig. 5, is. counterbored at 43 to receive the timing train for the fuse, such timing train consisting essentially of a top plate 44, a middle plate 45, and a lower plate 46, these plates being spaced apart from each other in the' usual mnner. The top plate is recessed on its top surface to receive the main spring 47, this recess being closed by a cover plate 48 attached to the top plate by screws 49, the inner end of the main spring 47 being attached to a hollow hub 50 which finds a bearing, top and bottom, in the cover plate. 48 and middle plate 45 respectively. Rotatable with the hub 50, but slidable longitudinally with respect thereto is a shaft 51, the upper end of which is non-circular in shape. as indicated by the numeral 52, for a purpose to be hereinafter described. The lower end of the shaft 51, as viewed in Fig. 5, extends downwardly through the middle plate 45 and is normally in enga ement with the upper end of a cup-shaped member 53 that is slidably mounted on a second cup-shaped member 54, the lower end of this cup-shaped member being threaded at 55 and screwed into a circular plate 56 mounted at the extreme lower end of the reduced portion of the body 10. Secured to the lower end of the hollow hub 50 adja"ent the middle plate 45is a main Wheel 57. This main wheel 57 communicates through appropriate gearthird wheel 60vwhich drives a fourth wheel 61 secured to a shaft 62 rotatably mounted in suitable bearings in the middle and lower ion plates 45 and 46 respectively. This fourth wheel 61, through appropriate gearing is connected with the escape pinion 63 secured to the shaft 64 rotatably mounted in bearings in the middle and lower plates 45 and 46' respectively and this shaft extends downwardly through the lower plate 46 and fits into a lower bearing in the'pallet bridge 65 secured to the under side of the lower plate 46 by screws 66. Secured to the shaft 64 between the pallet bridge 65 and the lower face of the lower plate 46 is the escapement wheel 67 and the rotative movement of this escape- ,ment wheel 67 is controlled by the escapement 68 that is, in turn, controlled by the balance wheel 69 attached to a shaft 70 rotatably mounted in the lower plate 46 and in the balance bridge 71, the movement of the balance wheel 69 being, in turn, controlled by the usual hair spring 72.

Located between the upper end ofthe cupshaped member 54 and the under face of the upper-end of the cup-shaped member 53 is the compression spring 7 3 which tends to force such cup members apart or the cup member 54, being immovable, the spring 7 3 tends to force the cup-shaped member 53 upwardly with respect thereto, as viewed in Fig. 5, thereby tending to move the shaft 51 longitudinally of the hollow hub 50. The hollow cup-shaped member 53 is provided with a longitudinal key way 9 in which fits a key 8 secured to the lower plate 46. This arrangement allows longitudinal movement of the cup-shaped-member 53 with respect to the lower plate 46, but prevents rotative movement thereof. Slidably mounted in the interior of the cup-shaped member 54 is a firing pin and between the upper end of the firing pin and the lower face of the upper end of the cup-shaped member 54 is a compression sprin 76 which tends to force the firing pin 75 ownwardly, as viewedin Fig. 5, out of the cup-shaped member 54. The

cup-shaped member 54 is provided with diav metrically arranged passages on either side of its axis to hold the balls 77 and it will be noted that the firing pin 75 intermediate its ends is provided with a V-shaped circular groove 7 8 in which the balls 77 fit, and also it will be noted that the cup-shaped member 53 is of suficient length, when the compression spring 73 is compressed, to practically cover the diametrically arranged holes in the cup-shaped member 54 and thus the cupshaped member'53 acts to retain the balls 77 in the position shown in Fig. 5 and such balls 7 7 fitting under these conditions in the V shaped groove 7 8, retains the firing pin 7 5 in its uppermost position, as viewed in ,Fig.

5, with the compression spring 76 under tension. The firing pin 75 is adapted to engage with a primer located in the primer holder 6 positioned in the line of movement of the firing pin 75.

The body 10 above the recess or counter-- bored portion 43 is recessed to receive a worm Wheel 83, such worm wheel being retained in rotatable position within said recess by means of a ring 84 secured to the body 10 by screws 85. The under face of the worm wheel 83 is provided with a noncircular recess 86 in which may fit the noncircular projection 52 on the upper end of the slidable shaft 51 so that, when the noncircular projection 52 comes into registry with the non-circular recess 86, the spring 73 will be allowed to expand, forcing the shaft 51 longitudinally withrespect to the hollow hub 50, this movement also forcing the cup-shaped member 53 upward a sufficient distance to expose the transverse hole through the cup-shaped member 54 whereupon the compression spring 7 6 will expand, forcing the firing pin 75 downward, simultaneously forcing the balls 77 out of the transverse hole. The worm wheel 83 is engaged and driven by a worm 87, rotatably mounted in a transverse hole in the body 10, the side of the body being recessed at 88 and the outer end of the shaft 87 extends into said recess. On the shaft 87 are two gears 89 and 90 respectively, the gear 89 being loose on the shaft while the gear 90 is fastened thereto. The outer face of the gear 89 is provided with graduations and se cured to the outer end of the shaft 87 is an indicating hand 91 adapted to cooperate with such graduations. The number of teeth on the shafts 89 and 90 differ by one tooth and I preferably make the number of teeth on the shaft 89 thirty seven and the 'number of teeth on the shaft 90 thirty six.

Rotatab'ly mounted. in the body 10 parallel to the shaft 87 'and within the recess 88 is a shaft 92 and secured to this shaft is a pinion 93 which meshes with both of the gears 89 and 90, the outer end of the shaft 92 being made non-circular to receive a. winding or setting key. The outer end of the recess88 is threaded to receive a cover plate 94 which protects the gearing 93, 89, and 90 and prevents the entrance of moisture or dirt to such gearing, it being understood, of course. that the cover plate 94 is entirely within the surface of the body member 10. By rotating the pinion 93 a sufiicient number of times to rotate the gear 90 through one complete revolution, the gear 89 will be rotated through a distance equal to one graduation thereon, said graduation being brought into registry with the indicating hand 91 and also simultaneously the non-circular recess 86 in the under surface of the worm wheel 83 will be rotated relatively to the non-circular projection .52 on the upper end of the shaft 51.

HIS

The body member 10 above the recess in j 1 extending upwardly therefrom is a stop pin 100 which isadapted to engage, on rotary movement of the worm wheel 83 in the direction of the arrow shown in Figs. 9 and 10, with the stop pin 101 secured in the body 10 and extending downwardly into the'counterbored portion 95. The stop pins 100 and 101 predetermine the neutral position of the worm wheel 83 and therefore the neutralpositionof the recess 86 with respect to the indicating hand 91 and graduated gear 89.

As above described, when the recess 86 is in registry with the non-circular projection 52, the expansion of the spring 73 forces the shaft 51 upwardly, as viewed in Fig. 5, and allowing movement of the firing pin.

Ordinarily the timing train is set of]? neutral so that the non-circular recess 86 and non-circular projection 52 are out of registry with each other and therefore accidental dropping of the bomb to which the fuse is attached will cause a setting in motion of the timing train and the detonation of the fuse after a short period of time. It may be, however, that the timing fuse will be inadvertenty set at neutral and ordinarily immediate detonation of the charge'of the bomb takes place. To. prevent this contingency happening, I have arranged a device that is associated with the timing train which will allow the fuse to be set at neutral and which will prevent detonation of the fuse until after the lapse of a predetermined time. This device consists of a slot 102 near the lower end'of the shaft 51 and normally engaging in such slot is a spring locking member 103. One end of this locking spring is secured to a in 104 fastened .to the under face of the mi dle plate and adjacent such end the locking spring passes through a slot in the pin 105 also secured to the under face of the middle plate 45.

This locking spring 43 extends radially of' the fuse, as shown in Fig. 14, and its outer free end is normally in engagement with the bevel face 106 of a member 107.

\It will be obvious from an inspection of Fig. 14 that the spring locking member 103 tends to rotate the member 107 in the direction of the arrow shown so that no appreciable amount of energy from the main spring 47 of the timing train is necessary to operate the device. The size of the pinion- 109 is so proportioned with relation to the main wheel 57 that a quarter revolution of the shaft' 108 will take approximately five minutes this time, however, being purely arbitrary and any other desired time may be utilized. As the shaft- 108 rotates in the direction of the arrow shown in Fig. 14, the spring locking member 103 is gradually moved from the position shown in full lines to that shown in dotted lines and, when this dotted line position is reached, the locking spring 103 is out of the slot 102, and, therefore, as far as the locking member is concerned, the shaft 51 is free to move longitudinally. This device was designed to obviate serious accidents. which have periodically occured in handling this type ofv device. With this device, regardless of whether or not the timing train is set at zero, and the timing train started in motion, at least five minutes must elapse before the fuse will be detonated which is found to be ample time for all persons in the immediate vicinity to get to a place of safety. I consider this an important feature of my invention and desire to claim the same broadl Secured to the hollow hub adjacent the main wheel 57 is a.radially extending arm 110 which is normally engaged by one ,arm of a bell crank lever 111 rotatably mounted on a shaft 112 in the lower face of the top plate 44 and secured to the other arm of said bell crank lever 111 and surarm 110. The rotation of the bell cranklever 111 by the spring 113 insures that the bell crank lever 111 cannot thereafter en gage with the radial arm 110.

The upper, middle, and lower plates 44,

45, and 46 respectively are drilled, as

shown in Fig. 5, to allow free passage of the lower end of the rod 2 5 and when in set position, the rod 25 is, engaged by one arm of the bell crank lever 111 and thereby prevents rotation of such bell crank lever about its shaft 112. That portion ofthe rod 25 below the point of its engagement with the bell crank lever 111 is cut away, as indicated by 115, so that if the rod 25 is moved upwardly, as viewed in Fig. 5, the cut away portion 115 will be brought 0p.- posite the end of the bell crank lever 111 which thereupon is allowedto rotate on its shaft 112. ssuming the rod 25 to be moved upwardly so as to release the bell crank lever, it will be obvious that the releasg of such lever will also cause the release of the radially extending arm 110 which, being fast to the hollow hub 50, will now allow such hollow hub 50 to rotate under the influence of the main spring 47 member '10 is rotated in a clockwise direction, engages 1n a groove or slot 117 in a member 118- extending upwardly and formed integral with the circular plate 56. The circular plate .56 on its lower. face is provided witha groove'. -119 in which is secured by rivet 120 a spring detent 121. Located below tlie'circularplate-56 and within the member 38, being secured such member byscrews 122 is a circular plate 123 pro vided with a centrally located passage 124 in the path of movement of the firing pin 75. On the upper face of the plate. 123 and arranged in a circle are a plurality of notches 124 with which the free end of the spring detent 121 engages. This arrangement of mechanism forms an additional safety device in the sense that this construction positively prevents the fuse body member 10 with attached parts being unscrewed from the nose of an aerial bomb 42. it being assumed that the members 38 and 40 are secured together against rotative movement as by a screw 125. Assume that the members 38 and 40 are screwed together, as shown in Fig. 5, and that a hole is drilled and tapped to provide for the insertion of the screw 125. If, now, the fuse body 10 with attached parts is screwed into the member 38 in a clockwise direction, this movement will be continued until the body member 10 is in the position shown, and as it approaches this position, the spring detent 121 will en gage with, and slip over the notches 1.24 in succession until the body member 10 is in its innermost position. All parts are as sumed to be in the position shown in Fig. 5. The entire device shown in Figs. 4 and 5 is screwed into the nose of an aerial bonib 42. Should it now be attempted to removethe body member lO and attached parts from the aerial bomb, the body member must be rotated in an anti-clockwise direction, as viewed in Fig. 5; Under these conditions, the pin 116 will move out of the' groove or slot '117 and as the body member 10 is rotated, it will move upwardly, leaving the circular plate 56 in position in engagement with the member 123. As the body member 10 moves upward, the spring 7 3 will expand, moving the cupshaped member 53 upward at the same speed as the body member 10 moves until the passage in .the cup-shaped member 54 is exposed and allows the balls 77 to fly radially outward whereupon the spring 76 Will force the firing pin 7 5 downward through the passage 124 and into engagement with the primer 77 which will detonate the fuse of the primer and therefore the explosive charge of the bomb. It will be seen, there-fore, that this mechanism provides means whereby the device-may be screwed into position without danger, but

"ployed for supporting the bomb 42 in position underthe lower wing 228. At the time of placing the bomb 42 in. position on the airplane 126, the cotter pin 32 is removed from the eyes a cord 129 attached to the eye 31 of the pin and the other end of this cord 129 is attached to any convenient portion of the airplane.

The operation of my improved device is as follows, it being .assumed that the body '10 with all attached parts, as above described, is secured to the head of an airplane bomb 42 and that the bomb is secured in position on the airplane 126 by holding devices 127 and 128. Also that the bomb is to be dropped into a designated place or spot, the object being to plantthe bomb and have the charge therein detonated a pre determined time after such planting, the lapse of'time between the planting of the bomb and the detonating of the charge being variable within extremely wide limits of from five minutes to two, three, or even more days. Before attaching the mechanism to the aerial bomb 42, the main spring 47 of the timing train is first wound in the usual manner, thespring arm 103 placed in a slot 102 in the shaft 51, the rod 25 inserted in the body member 10 until it engages with one arm of the bell crank lever 111. The ball '20 is placed on the top of the rod 25, the rod 16- placed on top of the ball 20 and the threaded member 13 screwed into the top of the body member 10. The pin 30 is inserted through the'hole 28 and into the hole 29 near the top of the pin 25 where it is held against withdrawal by the insertion of the cotter pin 32 through the eyes 33 and through the eye of such pin 30. Assuming that it is desired to load the device onto an airplane 126 for dropping and therefore detonation after a predetermined length of time, the plug '94 is withdrawn from the opening of the chamber 88 and by a suitable tool the pinion 93 is rotated to cause relative movement of the graduated gear 89 with respect'to the indicating hand 91 which will predetermine the time of detonating the charge. The device is now screwed into the members 38 and 40 which are secured together against rotative movement by the screw and the entire assem- 'bly is then screwed into the nose of an aerial '32 from the eye 31 of the pin 30 and attaches one end of the string 129 to such eye 31 and the other end of the string to any fixed part of the airplane. The airplane is now supposed to take flight and, on reaching the desired spot, the operator, by properly controlling the forward supporting device 128, releases the end of the bomb 42 which, by reason of its weight, falls nose down and drops out of the rear supporting device 127. The pin 30 being secured to the airplane 126 by the string 129, is pulled out of the body member and therefore out of the rod which is thus, other things being equal, in position to move longitudinally. Assume that the aerial bomb 42 drops nose down. On striking the ground, the shock of striking will be sufficient to cause a longitudinal movement of the pin 16 toward the nose end of the body member 10 in the passage 15 against the tension of the split holding ring 18 and the expansion of the helical spring will be suflicient to force the rod 25 upward, as viewed iaFigs. 4 and 5. This longitudinal movement of the rod 25 performs two functions. First, it forcesthe bevelled end 27 into close engagement with the bevel portion 24 on the interior of the member 22 and effectually prevents the entrance of moisture or dirt through the opening 28 in the body member 10. Second, it moves the lower end of the rod 25 out of engagement with the arm of the bell crank lever 111 and the spring 113 attached. to such bell crank lever rotates the same in the direction of the arrow shown in Fig. 12 and moving the other arm of such bell crank lever out of engagement with the end of the radial arm 110 on the hollow hub 50. The rotation of the bell crank lever 111 is sufficientto prevent a subsequent stopping of the timing'train should it be attempted to subject the aerial bomb and attached parts to a fur-- ther shock so that, once started in motion, the timing train will continue in motion until the charge is detonated. Immediately upon the starting of the timing train, the shaft 108 is started in rotation and after the lapse of a predetermined time, preferably five minutes, the spring locking lever 103 is moved out of the slot 102 and the shaft 51 is therefore placed in condition where it may be moved longitudinally. As the timing train operates, the shaft 51 is gradually rotated to bring the noncircular projection 52 thereon into registry with the non-circular recess 86 in the bottom face of the Worm wheel 83. When this condition occurs, the spring 73 forces the shaft51 longitudinally, allowing relative movement of the cup-shaped member 53 with respect to the cup-shaped member 54 sufficiently to expose the perforations in which fit the balls 77. When these perforations are exposed, the spring 7 6 will cause a simultaneous out ward movement of the ball 77 and a longitudinal movement of the firing pin which,

ing charge of the fuse which, in turn, detonates the main charge of the aerial bomb.

If the aerial bomb with the fuse body 10 and parts associated therewith drops bottom down, the shock of landing will be sufiicient to cause the pin 25 to compress the spring 35 and the ball 20, following the pin in this movement, will strike against'the upwardly extending pin 34 and be thrown laterally of the line of flight; that is, to the striking the primer 7, detonates the detonatright, as shown in Fig. 4. After the aerial bomb is stopped, due to striking the ground, the expansive force of the spring 35 will force the pin .25 upwardly, as viewed in Figs. 4 and 5. and will be enabled to do so because theball 20 is no longer in position between the pins 25 and 16. The operation of the device from this point is the same as that described above.

Assuming that the aerial bomb with at-' tached fuse strikes side on, or keyholes, the shock of striking will be sufficient to throw the ball 20.0ut of its position with respect to the rods 25 and 16 and thereupon the spring 35 will force the rod 25 upwardly, as viewed in Fig. 4, and the sequence of operations above described will take place from this point on.

It will be obvious from the above that my device will positively detonate the charge of an aerial bomb and also by reason of closing up the only inlet from without the bomb to the interior, which is the hole 28, I effectually prevent the ingress of moisture or dirt sothat, regardless of the length of time the bomb is exposed or regardless of the conditions at the place where it lands, no moisture will be able to penetrate to the interior of the bomb or the fuse.

Instead of setting the device by rotating the pinion 93, I may provide a non-circular portion on the shaft 87 that carries the pointer 91 and this construction enables me to make a quicker setting than could be made by the pinion 93.

,VVhile I have necessarily shown and described the preferred embodiment of my invention somewhat in detail, it is to be understood that I may vary the size, shape, and arrangement of parts within wide limits without departing from the spirit of the invention.

Having thus described my invention, what I claim as new is:

1.v In a fuse, the combination of a timing train, 'a slidably mounted shaft rotated by, and forming part of, the timing train, a noncircular projection on one end of said shaft, a setting device including a rotatable element provided with a non-circular recess associated with the timing train, and means for varying the relative position of said noncircular recess with respect to the non-circular projection.

2. In a fuse, the combination of a timing train, a slidably mounted shaft rotated by, and forming part of, the timing train, a noncircular projection formed on one end of such shaft, a rotatably mounted member'provided with a recess corresponding in shape and dimensions to the non-circular member or projection, and means for rotating the circular member relative to the non-circular projection- 7 3. In a fuse, the combination of a timing train, a shaft rotatably mounted by, and slidable with respect to, the timing train, a non-circular projection formed at one end of said shaft, a member provided with a noncircular recess, means for rotating said member to vary the position of the non-circular recess with respect to the non-circular projection, a firing pin, and means interposed between the firing pin and slidable shaft for simultaneously moving the shaft when the nonfcircular projection and recess are .brou' ght into alinement and releasing the firing pin 4. In a fuse, the combination of a cupshaped member provided with-diametrically arranged perforations, a firing pin slidably mounted within said cup-shaped member, a firing spring acting to force the firing pin outward with respect to said cup-shaped member, a second cup-shaped member slidably mounted on said first cup-shaped mem- 'ber and of sufficient length to cover said alined perforations, a groove in said firing pin, balls in said diametrically arranged perforations fitting into said groove and prevented from moving outward thereof by said second cup-shaped member, a compresvnon circular neeao'za sion spring located between the upper end of the first-cup-shaped member and the under face of the second cup-shaped member,

a non-circular projection formed on the up-' per end of the slidable shaft, a rotatably tive position of said recess and non-circular projection, means for rotating the slidable shaft to brin the non-circular projection thereof into a mement with the non-circular recess whereby the compression spring forces the projection into the recess and moves the end of said second cup-shaped member from the diametrically arranged holes to permit escape of the balls from the groove in the firing pin and allows the firing spring to actuate the firing pin.

5. In a fuse, the combination of a timing train, a shaft rotatably mounted by, and slidable with respect to, the timing train, a non-circular projection formed at one end of said shaft, a member provided with a non-circular recess, means for rotating said member to vary the position of the non-eir-' cular recess with respect to the non-circular projection, a firing pin, means interposed between the firing pin and slidable shaft for simultaneously moving the shaft when the projection and recess are brought into alinement and releasing the firing pin, and means associated with said shaft for preventing longitudinal movement thereof until the lapse of a predetermined time after the timing train has started in motion.

6. In a fuse, the combination of a firing pin, a timing train controllingthe operation thereof, a starting mechanism associated with the timing train, means movable longitudinally of the axis of the fuse for controlling the starting of the-timing train,

means for locking the last said means in inoperative position, and means for releasing the locking means when the fuse is dropped.

In testimony whereof, I have signed my name to this specification.

. FREDERICK W. BOLD. 

